2014: Statistically speaking, Flanagan had his best season in 2014. He led the Hounds with a personal record of 62 groundballs, which also ranked him sixth among all MLL players. Flanagan was a key contributor on the faceoff wing and in transition. He was named Warrior Defensive Player of the Week in Week 9, marking the first time he has received a weekly honor from the league. In addition, Flanagan was named to his third-straight MLL All-Star roster.

2013: Flanagan was named to his second-straight MLL All-Star Game in 2013. The defenseman in 12 regular-season games scooped up 34 groundballs and added another nine during the postseason. Flanagan during the Hounds’ Week 10 game against the Boston Cannons recorded his first MLL goal, and added another in the final week of the season against the Chesapeake Bayhawks.

2012: The Hounds acquired Flanagan through a trade with the Hamilton Nationals in October 2011. The defensman played in all 14 games of the franchise's inaugural season and was the Hounds’ anchor on defense. He collected a team-high 59 ground balls, 32 more than the next closest player (goaltender and faceoff not included). The defenseman also ranked third in the league for this category. Additionally, Flanagan was a 2012 MLL All-Star selection.

2011: Flanagan was selected by the Hamilton Nationals in the second round (7th overall) of the 2011 MLL Collegiate Draft. The defenseman was unable to play that summer though, because he underwent a series of surgeries to repair shattered bones in both feet and a sports hernia.

Collegiate: In four years at North Carolina, Flanagan played in 63 games, recording eight points (four goals, four assists), 193 groundballs and 108 caused turnovers. He was a three-time USILA All-American and the 2010 co-winner of the Schmeisser Memorial Cup as the nation's top defenseman. Additionally, Flanagan served as a team co-captain in 2011.